As known, an optical disc drive is used to read data from an optical disc or write data into the optical disc. Conventionally, the optical disc has two layers, i.e., a label layer and a data layer. Since the label layer does not record data, the user may write characters or marks on the label layer with a pen. The data layer is used for recording digital data.
Generally, the optical disc drive has an optical pickup head. For accessing the data of the optical disc, the optical disc is firstly loaded into the optical disc drive. When the optical disc is loaded into the optical disc drive, the data layer of the optical disc faces the optical pickup head. After the optical disc is rotated by a spindle motor, the laser beam emitted by the optical pickup head can access the digital data on the data layer of the optical disc.
As mentioned above, the optical disc has the label layer for identification so that when the optical disc is loaded into the optical disc drive, it is difficult to reversely place the optical disc in the optical disc drive. And the data of the optical disc can be accessed when the optical disc is rotated in a single direction.